Feeding device for grinding mills



(NoM 0d'e'-1.) I

W. D. GRAY.

- FEEDING DEVICE FORQGRINDLING MILL-S, N0.'261,337 Patented July 18, 1882.

UNITED, STATES PATENT OFFICE.

WVILLIAM D. GRAY, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO EDWARD P.

ALLIS, OF SAME PLACE.

FEEDING DEVICE FoR GRINDING-MILLS.

SPECIFICATION forming part of Letters Patent No. 261,337, dated July 18, 1882.

Application filed November 1, 1881. (No model.)

To all whom it may concern Be itknown thatLWILLIAM DIcKsoN GRAY,

of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain Improvements in Feeding Devices for Grinding- Mills, of which the followingis a specification.

To this end the invention consists in com-' bining with an ordinary feed-roll in the bottom of a hopper a second roll located immediately over the feed-roll, provided with longitudinal ribs and freely exposed to the mass of superincumbent material in the hopper. The second roll serves to sustain, in a great measure, the weight of the V superincumbent mass of material, to agitate and loosen the same, and to deliver it to the feed-roll in such condition that the latter will carry it regularly and evenly to the grinding-rolls. The ribs or teeth of the supplemental roll may be straight or spiral, and may be continuous or broken, as preferred, it being preferred, however, to use continuous ribs and to drive the upper roll in the opposite direction from that in which the lower roll is turned.

Referring to the accompanying drawings, Figure 1 representsa vertical cross-section, showing my feeding apparatus in connection with a pair of grinding or crushing rolls. Fig. 2 is a side elevation of the rollers, with the hopper shown in vertical section on the line 2 2 of Fig. 1, also showing the manner in which the two feed-rolls are driven.

A A.represent two co-operating grindingrolls, which may be constructed, mounted,'and

the feed-roll 0, parallel thereto. The roll D is constructed, as shown, with longitudinal ribs or teeth I), and is connected at its outer end by a pinion, d, with a driving-pinion, c,

mounted on the outer end of the roll (J, this arrangement causing the two rolls'O D to turn in opposite directions.

When the machine is in operation the mass of material within the hopper is largely sustained by the roll D, its weight being in a great measure removed from the roll 0.

The rotation of .the roll D serves to'loosen the mass of material at its base and to feed the same steadily and in a free loosened condition to the roll 0, by which it is delivered in a continuous uniform stream through the discharge-opening to the grinding-rolls.

Fair results may be secured when the roll D is turned in the same direction as the'lower feed-roll; but it is preferred to turn the two rolls in opposite directions, inasmuch as a betteraetion is thereby secured.

I am aware that a toothed feeding-roll has been arranged in a feed-hopper in such manner as to co-operate with the lower edgeof a pendent spring-plate which was vibrated by the action of said teeth thereon, the plate assistin g to sustain the material and permitting the same to fall intermittently past the roll as the plate is forced backward by the latter. This I do not claim, my invention being restricted to an arrangement wherein the supplemental feed-roll is exposed directly and without intervening parts to the mass of material above, whereby the material is permitted to feed down upon and past said roll continuously and in a uniform manner.

Having thus described my invention, what I claim is- 1. The combination of the hopper and the with longitudinal ribs and mounted within the hopper immediately above and parallel with the first-named roll, a free unobstructed space being left for the passage of the mate- 5 rial continuously downward past the upper roll, as described and shown.

3. In combination with the hopper B and the feed-roll 0, located thereunder, the second feed-roll, D, provided with the longitudinal ribs, and mounted in a free uncovered po- [0 sition within the hopper, immediately above the roll 0, and driving mechanism, substantially such as described and shown, adapted to drive the rolls in opposite directions.

WILLIAM DIOKSON GRAY. Witnesses:

GEORGE M. HINKLEY, THEODORE F. WAMBoLD. 

